Dr. Cornelius is a tenure-track Assistant Professor in the Department of Medicine, Division of Dermatology at Washington University in St. Louis. She began this position January 1, 1993 after completing a three year research fellowship under the tutelage of Dr. Thomas J. Lawley at Emory University. During this period, training and expertise in the culture and biologic behavior of small and large vessel endothelial cells was obtained. Her long-term goal is to become an independently funded research scientist, studying endothelial cell biology. Dr. Howard Welgus, Chief and Professor of Dermatology at Jewish Hospital, and Dr. William Parks, Associate Professor of Dermatology, are part of a large and interactive connective tissue biology group based at Jewish Hospital, and will provide close scientific direction and guidance to this project. Wound healing and angiogenesis are complex processes which involve endothelial cell proliferation, migration, and in many instances, dissolution of extracellular matrix. In vivo, endothelial cells reside upon a basement membrane composed of matrix molecules which must be traversed by the endothelial cell destined to form new vessels. Matrix metalloproteinases (MMP) are a family of enzymes which degrade matrix components, allowing the cells that secrete them to efficiently traverse through connective tissue structures. We hypothesize that the secretion of MMPs by microvascular endothelial cells (MEC) is an integral, if not fundamental, component of new vessel formation. We have already defined the spectrum of MMP expression by MEC in response to certain cytokines and growth factors, including TNFalpha and bFGF. In this grant, I propose to study endothelial cell MMP production during angiogenesis. Based on our preliminary studies, I hypothesize that a coordinated and temporally defined synthesis of specific MMPs occurs during the different stages of angiogenesis. To evaluate this, cultured endothelial cells will be studied for in vitro MMP expression during endothelial cell migration, representative of the early stage of angiogenesis. Similarly, endothelial cell MMP expression will be evaluated during in vitro tube formation, representative of the later stages of new vessel formation, or differentiation. In vivo, tissue sections from diseases involving endothelial cell proliferation and/or states of abnormal angiogenesis will be studied. Assays combining in situ hybridization and immunohistochemistry will also be used to specifically identify endothelial cells, and spatially correlate MMP, cytokine, and extracellular matrix production. The molecular mechanisms of MMP production by endothelial cells will be determined. Pre-translational control will be established by Northern hybridization; transcriptional regulation will be assessed using nuclear run-off assays. Promoter deletion studies will identify specific cis-acting elements important for regulation. Involved trans-acting factors will be determined using mobility shift assays. If induction is not under strict transcriptional control, mRNA stability will be assessed by utilizing inhibitors of RNA synthesis. It is anticipated that through these studies, invaluable insights will be gained into the expression of metalloenzymes by microvascular endothelial cells during angiogenesis.